*, *::after, *::before {
    box-sizing: border-box;
}

:root {
    --cell-size: 150px; /* Increased cell size */
    --mark-size: calc(var(--cell-size) * .9);
}

body {
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: white; /* Static white background */
}

.container {
    display: flex;
    size: 50px;
    gap: 50px; /* Space between form and game board */
}

.player-input {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: 10px; /* Reduced padding */
    border: 20px solid #333;
    background-color: #f4f4f4;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    width: 500px; /* Reduce width */
}

.player-input h2 {
    margin-bottom: 10px; /* Reduced margin */
    font-size: 18px; /* Smaller font size */
}

.player-input label {
    margin-bottom: 3px; /* Smaller margin between label and input */
    font-size: 14px; /* Smaller font size */
}

.player-input input {
    margin-bottom: 10px; /* Reduced margin */
    padding: 5px; /* Smaller padding inside input fields */
    width: 180px; /* Reduced input width */
    font-size: 14px; /* Smaller font size */
    border-radius: 5px;
    border: 1px solid #ccc;
}

.player-input button {
    padding: 5px 10px; /* Smaller button */
    font-size: 14px; /* Smaller font size */
    background-color: #007bff;
    color: white;
    border: none;
    cursor: pointer;
    border-radius: 5px;
    width: 100%; /* Make button fill the width of the form */
}

.game-section {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, var(--cell-size));
    gap: 10px;
    justify-items: center;
    align-items: center;
}

.cell {
    width: var(--cell-size);
    height: var(--cell-size);
    border: 5px solid #333; /* Thicker border */
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    cursor: pointer;
}

.cell.x::before, .cell.x::after {
    content: '';
    position: absolute;
    width: calc(var(--mark-size) * .15);
    height: var(--mark-size);
    background-color: #333;
}

.cell.x::before {
    transform: rotate(45deg);
}

.cell.x::after {
    transform: rotate(-45deg);
}

.cell.o::before {
    content: '';
    width: var(--mark-size);
    height: var(--mark-size);
    border: calc(var(--mark-size) * .1) solid #333;
    border-radius: 50%;
    position: absolute;
}

.winning-message {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    color: white;
    font-size: 24px;
    z-index: 10;
    opacity: 0;
    transition: opacity 0.5s ease;
}

.winning-message.show {
    display: flex;
    opacity: 1;
}

.winning-message button {
    margin-top: 20px;
    padding: 10px 20px;
    font-size: 18px;
    background-color: #007bff;
    color: white;
    border: none;
    cursor: pointer;
    border-radius: 5px;
}

#playerTurn {
    font-size: 24px;
    margin-bottom: 20px;
    font-weight: bold;
}